The present invention relates to heating devices of the type employing a blower to force air into a combustion chamber, where oxygen in the air reacts chemically with a fuel, such as oil or gas, to cause burning of the fuel. Oil burners used in space heating applications are conventionally of this type. In particular, the present invention relates to an improved design of fuel burner and a method and device for improving the performance of conventional designs of such a fuel burner.
Fuel burners are used, for example, both in furnaces and in boilers. Convection, steam, and other methods are used to accomplish transfer of heat resulting from combustion sustained through operation of these devices. In practice, fuel burners are often designed to cause the air to enter the combustion chamber co-extensively with the fuel to be burned. When the fuel is oil, the oil is generally atomized or vaporized and thereafter caused to mix physically with the air and to flow into the combustion chamber with it. This air-fuel mixture then burns by reacting chemically in the combustion chamber.
Various methods of improving the performance of fuel burners are known in the prior art. Some of these methods, pertinent to the invention described herein, operate by enhancing, in the furnace's combustion chamber, the extent of turbulence in the flow of the air-fuel mixture. Such additional turbulence has been created by the insertion into the combustion chamber of objects having surfaces specially shaped so as to tend to break up any smooth flow of the air-fuel mixture in the combustion chamber. Such additional turbulence has also been created in the prior art by employing an object to modify the flow of the air-fuel mixture at the point where it first enters the combustion chamber.
In U.S. Pat. No. 3,918,885, issued for an invention of B. O. M. Palm et al., there is disclosed an apparatus and method for reducing the dynamic pressure of air that has been blown by the blower at the burner head of an oil-burning appliance. The invention utilizes a series of baffles to form a labyrinthine path for the air to flow between the output of the blower and the burner head. Certain other embodiments are disclosed that involve use of small turbines and slotted members, through which the air is required to pass. Generally, the labyrinthine structure is confined to the blast tube, and requires a plurality of baffles. Where baffles are not used, more complicated structures are employed. These structures are not readily conducive to modification of existing oil burners, and may depend on different physical principles for their successful operation. Nowhere does the patent refer to the use of a single protrusion for improving the performance of fuel burners, and nowhere does the patent disclose the use of an air-deflecting object in the blower housing itself.